a. Field of the Invention
The present invention relates to a membrane for a loudspeaker with enhanced acoustic properties. This invention furthermore relates to a micro speaker optimized for high acoustic output and located within a small volume of a mobile device, such as a mobile phone, a tablet, a gaming device, a notebook or similar device.
b. Background Art
Prior art membranes comprise a central portion with a sound emitting surface area and a back surface area located opposite the sound emitting surface area, wherein the sound emitting surface area and the back surface area of the central portion constitute at least 60 percent of the overall surface area of the membrane. The membrane further comprises a first edge directly adjacent to the central portion and surrounding the central portion, wherein the first edge constitutes a boundary line between the central portion and an adjacent area comprising a different surface curvature than the central portion. Furthermore, the membrane comprises a second edge surrounding the first edge, a clamping collar for mounting the membrane to the loudspeaker, wherein the second edge directly merges into the clamping collar and an intermediate portion located between the first edge and the second edge.
CN203225873 U discloses a membrane of the above mentioned kind. The membrane has a rectangular structure, wherein the intermediate portion comprises protrusions for reinforcing the intermediate portion of the membrane.
CN204887418 U relates to a membrane with a central portion and a ring portion, wherein the ring portion comprises ridges protruding from the ring portion.
CN203984657 U discloses s membrane comprising a spherical top in the middle, and a ring part on the outer periphery of the spherical top. The ring part is protruding out of a plane where the spherical top is located and is provided with a plurality of reinforcing protrusions to increase strength of the membrane.
WO15131821 A1 relates to a speaker vibration system comprising a diaphragm body part and a voice coil combined at a lower side of the diaphragm body part. The speaker vibration system comprises a rigid dome part, a silicone rubber membrane and a plastic stent combined at an edge of the silicone rubber membrane. The dome part is arranged at a middle position of the silicone rubber membrane. A ring part is arranged at a position that is located at an outer side of the dome part on the silicone rubber membrane. The ring part is either concave or convex shaped.
DE1277930 B discloses an elliptic membrane with a tubular vibration part surrounded by a ring comprising grooves.
A particular drawback of known membranes are their acoustic properties. It is a further drawback of the known membranes that they require a lot of mounting space, which is a major problem with regard to micro speakers.